I've come to know a lot of pilots that instruct, and most of them haven't done basic circuits in decades. A girl that lives a couple of streets down does Cirrus specific training, both initial and insurance qualifying. She also picks up and ferries Cirrii. Another one is an Aerostar and MU-2 instructor and does the insurance company approved initial training. A third one delivers singles and twins all over the US/Canada/Mexico. He's always busy, charges flat fee of $500/day + expenses for all ferries. A fourth one is a DPE (examiner in the UK) and he's got checkrides almost every day at $600/pop...
So, depending on how you specialise, you can certainly make a more than decent living doing instruction, without ever having to beat out circuits in a Cessna.